1. The Field of the Invention
The present invention relates to lineshaft turbine pumps and, more specifically, shaft assemblies for lineshaft turbine pumps.
2. Present State of the Art
Lineshaft turbine pumps are uniquely configured for pumping fluids through large elevational differences such as from the bottom of wells or mines. A typical lineshaft turbine pump includes an elongated hollow pipe having a bottom end that is selectively positioned within the fluid to be pumped, such as in the bottom of a well. Positioned at the bottom end of the pipe is shaft driven pump. The top end of the pipe is positioned at ground surface and has a discharge head attached thereto. The discharge head is fluid coupled to the pipe and has a discharge port which exits through the side thereof. A discharge line is fluid coupled to and extends from the discharge port.
Mounted to the discharge head in axial alignment with the pipe is a packing container. The packing container has a passageway longitudinally extending therethrough. Positioned above the packing container is a motor. A drive shaft is rotatably positioned within the passageway of the packing container. The drive shaft has a first end engaged with the motor and an opposing second end disposed within the discharge head below the packing container. A line shaft is disposed within the pipe. The line shaft has a first end coupled to the second end of the drive shaft and an opposing second end that is coupled to the pump. During operation, the motor rotates the drive shaft which in turn rotates the line shaft. Rotation of the line shaft operates the pump which draws water from the exterior into the pipe. The water flows up the pipe and out the discharge head through the discharge port and discharge line.
The function of the packing container is to seal around the drive shaft such that fluid passing through the discharge head can exit only through the discharge port and not leak out around the drive shaft. To effect this seal, the packing container includes a soft packing material which is tightly compressed around a portion of the drive shaft positioned within the packing container. The packing material enables the drive shaft to freely rotate within the packing container while effecting a liquid tight seal.
After extended periods of operation, the packing material can wear away at the drive shaft, eventually resulting in fluid leaking thereat. To stop the leaking, it is necessary to replace the drive shaft. Conventional designs of lineshaft turbine pumps, however, can make replacement of the drive shaft extremely difficult. Initially, the drive shaft must be separated from the line shaft. The ends of these two shafts are initially coupled together by each screwing into opposing ends of a threaded coupler. Rotation of the drive shaft, however, results in the drive shaft being tightly threaded into the coupler.
Separating these two elements requires an individual to remove the discharge line and then reach into the discharge head through the discharge port with a wrench. As the coupler is held stationery by one wrench, an opposing wrench positioned above the packing container and below the motor is used to loosen the drive shaft. Minimal space within the discharge head makes it extremely awkward and very difficult to position and manipulate the wrench therein. Furthermore, it is difficult to obtain the proper leverage often necessary to loosen the rigid connection.
Frequently, it is impossible for an individual to disconnect the drive shaft from the threaded coupler. In such situations, it is necessary to remove the motor from off the discharge head and thereby provide access to the drive shaft by disassembling the system. This process is very expensive since it requires a large crane to lift the motor for removal and results in extensive down time during disassembly and then reassembly of the system.